The EPA issues a new rule to strengthen the protection of water in the US.

The Environmental Protection Agency and the Army Corps of Engineers announced a new definition of “united states waters”, a classification that has been debated for decades.

The question is what types of waterways (wetlands, rivers, lakes, etc.) are protected by the Clean Water Act, which was signed into law 50 years ago. The law regulates water contaminants and empowers the EPA and the Army Corps of Engineers to define which particular bodies of water are protected by law. Protected water bodies qualify for federal programs related to oil spill prevention, water quality regulation, and more.

During the Obama administration in 2015, the EPA established a relatively broad framework definition of United States waters, or WOTUS, which included navigable waters such as the Mississippi River and the Pacific and Atlantic Oceans, as well as rivers, lakes, and wetlands that crossed state lines. But in 2020, the Trump administration limited the types of waterways that received federal protections, excluding much of the country’s smaller wetlands and waterways.

The new definition announced this week establishes protections similar to those that existed before 2015, while clarifying certain qualifications for protected waters.

Like the 2015 rules, navigable waters, oceans, and interstate waterways are protected by default. Tributaries flowing into and affecting larger water bodies can also be protected, as well as wetlands near protected waters and some additional lakes and ponds. To qualify, these smaller waterways must meet a set of standards that focus on their permanence and their interconnection with other bodies of water. These updated standards are, in part, a response to various Supreme Court decisions in cases challenging previous definitions of WOTUS over the past two decades.

In a news release, the EPA said the new rule is intended to “reduce uncertainty from changing regulatory definitions, protect people’s health, and support economic opportunity.”

“What we’re doing with this final rule is establishing a clear and reasonable definition of the waters of the United States,” said Radhika Fox, deputy administrator for EPA’s Office of Water.

He added: “We set water quality standards for lakes and streams across the country, and that’s what ensures that if you’re eating from that lake and if you’re swimming in that stream, it’s safe for you.”

The new rule also establishes some exclusions from WOTUS: wetlands that were converted to farmland before 1985, waste treatment centers, ditches, areas with artificial irrigation, artificial lakes and ponds, and artificial swimming pools.

“This comes at a time when we are seeing unprecedented attacks on federal clean water protections by polluters and their allies,” said Jon Devine, director of federal water policy at the Natural Resources Defense Council. “While the nation still has much work to do to fully protect important waters, it is encouraging to see the country taking a step in the right direction to protect the waters we need for everyone’s health and the environment.”

The Supreme Court will issue a decision next year in a case challenging the EPA’s determination that a privately owned wetland in Idaho is protected under the Clean Water Act. That decision could affect future rules on WOTUS.

Changes to the definition of WOTUS during past presidential administrations have led to lawsuits.